<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <title>有新内容吗</title>
</head>
<body>
<h1>Welcomte to Example ba</h1>
<div id="whatsNew"></div>
<script>
    var lastUpdated = new Date('Tue, 28 Dec 2020');
    var lastVisit = localStorage.lastVisit;
    if (lastVisit) {
        lastVisit = new Date(lastVisit);
        if (lastVisit < lastUpdated) {
            document.getElementById('whatsNew').innerHTML = '<a href="example-3b.html">What\'s New?</a>';
        }
    }
    localStorage.lastVisit = new Date();
</script>
</body>
</html>